Automatic fluid controlled transmission



NGV- 23, 1948- R. F, Gll-:BB 2,454,694

AUTOMATIC` FLUID CONTROLLED TRANSMISSION "Filed July 9, 1945 INVENTOR. Ro/SRT E GRf.

BY K

ATTORNEY.

Patented Nov. 23., 1948 UNITI-:D STATES vi-'nlx'rlezlv'r OFFICE AUTOMATIC `FLUID CoNTRoLLEn TRANSMISSION 1 Robert F. Grebb,` Boise, Idaho ApplicationJuly 9, 1945, Serial'No. .603,921

, 1 This invention relates to an automatic power transmission and has for its principal object' the provision of a simple and highly efficient speed change mechanism which willhave no shifting parts and in which the gear ratio orftorq'ue despeed increases. l l

Another object ofthe invention is tofprovide a device of this character in which the 'gears will remain in meshat all times so as to reduce" tooth wear and damage.

A further object of the invention is 5to, so construct the device that thegear ratiowill be automatically controlled through a vfluid medium without the use of mechanical shifting mechanisms. y

Other objects and advantages reside inthe detail construction of the invention, whichis designed for simplicity, economy, and efficiency.

livered will be automatically Adecreased as the These will become more `apparent from the fol' lowing description. Y Y

In the following detailed description of theinvention reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing: l

Fig. 1 is a longitudinal section through the improved automatic power transmission; and

Figs. 2 to 5, inclusive, are cross sections through the automatic shifting device, taken on the lines of their respective numerals, in Fig. 1.

In Fig. 1, a drive shaft through which the power is furnished to the transmission is indicated at I and the driven shaft receiving its power from the transmission ,is indicated at II. The shaftsl and are journalled in suitable bearingsIZ in an outer gear case I3 of any desired design. The extremity of the driven shaft is rotatably journalled in the extremity of the drive shaft Hl'I so that it may rotate relative thereto. g, I

The drive shaft IIJ -terminates in a drivegear |4 which is in constant mesh with a first set of planet gears I5 supported from and journalled on a planet gear spider I 6. The spider I6 is in turn journalled on the driven shaft l0 and is provided with a hub I1, extending therealong, which carries a sun gear I 8.

The sun gear I8 is in constant mesh with a second set of planet gears I9 which are supported thereabout upon a second planet gear spider 20, the hub of which, indicated at 2|, extends along and is journalled on the driven shaft II. A second sun gear 22 is keyed on the hub 2| and is in 2 constant mesh with a third set of planet gears 23. The third set of planet gears' are supported from the third planet gear spider 24, the hub of which iskeyed to the driven shaft II.

A rotatable drum 25 concentrically surrounds all of the gears. 'I'his drum carries a firstring gear 26 meshing With the rst set of planet gears '|5, a second ring gear 21 meshing with the second set of planet gears I9 and a third ring gear 28 meshing with the' third set of planet gears 23. The ring gears 2B, 21 and 28 are secured to and rotate with the drum 25.

A partition disc 29 extends inwardly from the drum 25 at each side of the second set of planet gears to form a fluid chamber thereabout. In use, the chamber is partially iilled with oil so that, when at rest, the lowermost portion of the ring gear 21 and the lowermost planet gear I9 are submerged. When the drum is rotating, however, the supply of oil spreads in a ring around the entire interior between the partition discs 29 so that the entire ring gear 21 and the intermeshing planet gears I9 are emersed in the ring of oil. The partition discs prevent the oil `from overflowing to the planet gear sets I5 and 23.

The spider 2|l supports an annular ring plate .30 and a similar ring plate 3| is supported at the opposite side of the planet gears I9 upon the `shafts thereof. The ring plates are closely spaced to'two annular side plates 32 at each side of the ring gear 21. The plates 30, 3| and 32`form an enclosure about the ring gear and tend to retain the oil thereabout. The plates 3|) and 3| also act to support separating blocks 33 between the plan,-

et gears I9 to ll the spaces therebetween so as to 'confine the oil to the cavities around the gear `teeth. The blocks 33 may be secured to the plates 3U and 3| in any desired manner such as Iby means of cap screws 34.

The first and Vthird planet gear sets l5 and 24 are simply for the purposes of spaced reduction and form no part of the automatic portion of the transmission.

. Operation As illustrated, if the drum 25 were prevented from rotating, the drive gear I4 would rotate the planet gears I5 around the inside of the ring gear 26 causing the spider I6 to rotate the sun gear I8 at reduced speed. The sun gear I8 in turn would rotate the planet gears I9 around the inside of the ring gear 21 causing the spider 20 to rotate the second sun gear 22 at further reduced speed. The sun gear 2.2 in turn would rotate the planet gears 23 about the inside of the ring gear 28 causing the spider 24 to rotate the driven 3 shaft I l at still further reduced speed. Since the drum 25 is free to rotate, however, the reactive force of the planet gear sets will rotate the drum rearwardly at the slowest impressed speed so as in mesh with said drive gear; a first planet gear spider supporting said first planet gears; a hub on said spider; a sun gear mounted on said hub; a second set of planet gears surrounding and in to still further reduce the speed of the driven 5 mesh with said sun gear; a second planet gear shaft I l. In fact, if the drive shaft is rotating slowly and the load on the driven shaft is suiciently heavy, the driven shaft will remain stationary;

spider supporting said second set of planet gears; a driven shaft operatively connected with said second spider; a drum surrounding all of said gearsz'ia firstafring gearrpositioned in and carried The interrneshing of the teeth of the second =by. said drunrinmeshwith the flrst'set of said planet gear set I9, however, is resisted by the trapped oil. The blocks 33 fit relatively closeto"l the teeth of the planet gears I9, the sunfgear I8,- and the ring gear 21. Therefore, the teethaaof;

planet gears; a second ring gear xed in said drum in mesh with said second set of planet gearsg,.andanannular side plate securedto and extending inwardly from said drum at each side of these gears act in the nature of a gear pump to said second set of planet gears; an annular rotatforce the oil along the passages between-the block 33 and the gears. For instance, let. usas sume that the drum and ring gear 21 are being forced in a counter-clockwise direction. Thisv able ring'. plate positioned inside of each side plate and forming a continuation thereof to form, in combination with said side plates, a fluid chamberto. retain iiuid about said second planet gears rotates the planet gears i9 both collectively and 30 and said second ring gearindividually around-the sun gear 18min-af counterclockwise direction. This causes the teeth of the ring... gear 21 and the `teeth'on thetrailing sides of the planetl gearsA i9 to pump-theoil: into the 2. Anf automatic powertransmission comprisingr. a.drive.shaft; adrive gear. on: said. drive shaft aviirsty set` of ...planet .gears surrounding. and in mesh-,With said'gdriV-e egear.; a .irst `planet gear notches'where the teeth ofthesegearsintermesh. 2:5.,Spider,supportingi said=first planet gears; a hub This oil must return past the advancing` teeth through the narrow passages.

This; of course,l creates -back pressurefupon the teeth ina manner similar to the restricting-of` the on saidyspider; a sungear mounted on'said hub; a second set of planet gears surroundingfand--in mesh-with'said:I sun gear.; a. second. planet` gear spider, supporting `said second setofY planetA gears;

discharge-,from any gear pump and resists-relamg),al drivenzshaft.. operatively connectedwith said tive rotation between the gears Iilandthe ring gear 21. This resistancefreacts against. the-sun gear.- so that the.rearward.movement ofthe drum willbel gradually reduced-until a'pointis reached second spider; a drum surroundinggall:l of,v said gears; a, i'lrst-.ringageanpositionedtimand carried by said drumizinmesnwiththe-first set` of'said planet gears.; a seondaring-:gearf fixedfinI said wnen-.tneurumwi-u rotatewith the-Sangean latas drum-in mesh with saidsecond Set of: planet and. delivers the fullspeed oithe'latter to'the second sun gear 22. This full speed will be only attainedy with light loads on the driven shaft. Heat/ier lea-dsv will. result in slippage or: relagears; an annular side plate secured to and extendinginwardly-'from said druiniateach side of saidsecondsetof planetfgears; an' annular rotatable ring plate positioned insidefoffeach-l side plate tive-.movementfbetween the-gears .IQ-andthe.drumiLiO-andffming ar-ontinuatiOn ther-@0f t0 fOIm, in

25; depending upon the torque-requiredin the driven shaft.

As` soon asthevspeed ofthe shaft; Illy is'. decreased, thequantity ofoilbeing pumped-and combination with said side plates', a=fluid` chamber tov retain:v fluid aboutsaidlsecond' planet gears and-saidsecondiring gear; separating blocks secured.: to and extending .between said .ring plates the pumping 10aa win decrease. snowing the-.45 andibetweenl theveea'rsof saidsecondset 0f planet Igears .of the set l'to rotate thesdrum'rearwardly to allow'the `driven shaft to slow downand eventually come to rest.

It canfbe readily seen fromv the above ythat an automaticallyl changeable gear ratio is providedio from theY free running stage through a direct connected stage to an overdrive or multiplied speed stage:

While=a-specicform of the improvementhas been described and illustrated.v herein, it isv desired v toabe` understoodfthat the same may ber varied,

within the-scope'of the appended claims, Without departing from the spirit of the invention'.`

Having thus described'the invention, what` is claimed and desired: secured byfLetters Patente() 1v. Anautomatic power transmission comprising: a drive shaft; a drive gear onusaidA drive Shaft; a rSt set of .planet gears surrounding and planet gears, saidblocksconforming inshape'to the curvature of the planet and/ring gears being supported :by said second f. planet gear spider.

ROBERT F. GREBB.

REFERENCES f CITED- The following referencesl aref of? record in the 'l'e of thispatent': 

